What do you think about the idea of adding the geo location of the shipping address to the request shopify send us?
I'm sure many CarrierService API apps are using an external service to geocode the address, which takes most of the response time.
And since Shopify geocode it anyways (You can tell based on the nice map in the thank you page), why don't you give this data to us and shave off very valuable seconds?
Shopify has not touched the request payload since it was launched oh so many years ago. When they do make changes, expect it to be a complete re-write/change, where the old clunky apps will have to adjust to new paradigms. Expecting them to tinker at this point with what is clearly an outlier service, in my best guess, is a low probability. But, you can wish!
@amosmos the map on the thank you page does not mean Shopify is geocoding the address during the actual carrier service API request/response... that would slow things down (however slightly) on their end which seems to be the opposite of the direction this is all moving in.
Anyway, just setting expectations here as it's never as easy as it sounds.
I am in favor of your request and enriching this whole API.
I agree with @HunkyBill. Unfortunately this endpoint has been neglected over the years and will likely continue to remain so ... for example, sending cart attributes & discounts seems like a basic next step.